The present invention relates to respiratory therapy devices. More particularly, it relates to percussive respiratory devices that deliver high frequency pulses of air to a patient during the patient's inspiratory and expiratory cycles.
A wide variety of respiratory therapy devices are currently available for assisting, treating, or improving a patient's respiratory health. For example, positive airway pressure (PAP) has long been recognized to be an effective tool in promoting bronchial hygiene by facilitating improved oxygenation, increased lung volumes, and reduced venous return in patients with congestive heart failure. More recently, positive airway pressure has been recognized as useful in promoting mobilization and clearance of secretions (e.g., mucus) from a patient's lungs. In this regard, positive airway pressure in the form of high frequency oscillation (HFO) of the patient's air column is a recognized technique that facilitates secretion removal. In general terms, HFO reduces the viscosity of sputum in vitro, which in turn has a positive effect on clearance induced by an in vitro simulated cough. HFO can be delivered or created via a force applied to the patient's chest wall (i.e., chest physical therapy (CPT), such as an electrically driven pad that vibrates against the patient's chest), or by applying forces directly to the patient's airway (i.e., breathing treatment, such as high frequency airway oscillation). Many patients and caregivers prefer the breathing treatment approach as it is less obtrusive and more easily administered. To this end, PAP bronchial hygiene techniques have emerged as an effective alternative to CPT for expanding the lungs and mobilizing secretions.
Various treatment systems are available for providing the respiratory therapy described above (as well as other therapies and/or ventilation). For example, intrapulmonary percussive ventilation (IPV) therapy relates to HFO devices that deliver pulses of air into the patient's airway opening. In general terms, an IPV system includes a hand-held device establishing a patient breathing circuit to which a source of positive pressure gas (e.g., air, oxygen, etc.), is fluidly connected. The pressure source and/or the device further include appropriate mechanisms (e.g., control valves provided as part of a driver unit apart from the hand-held device) that effectuate intermittent flow of gas into the patient breathing circuit, and thus percussive ventilation of the patient's lungs. With this approach, the patient breathes through a mouthpiece that delivers high-flow, “mini-bursts” of gas. During these percussive bursts, a continuous airway pressure above ambient is maintained, while the pulsatile percussive gas flow periodically increases airway pressure (e.g., the gas flow cycles the delivered pressure). Each percussive cycle can be programmed by the patient or caregiver with certain systems, and can be used throughout both inspiratory and expiratory phases of the breathing cycle. Examples of IPV devices include IPV® ventilator device (from PercussionAire Corp. of Sandpoint, Id.), IMP 2™ (from Breas Medical of Molnlycke, Sweden), and PercussiveNeb™ System (from Vortran Medical Technology, Inc., of Sacramento, Calif.). Also, U.S. Pat. No. 7,191,780 describes an IPV-type treatment apparatus, connectable to a source of pressurized gas, that requires a shrouded, fixed venturi tube for delivering the desired therapy.
In light of the promising nature of IPV therapy devices, any improvements to known designs, such as enhanced performance, long-term reliability, reduced manufacturing costs, ease of operation, etc., will be well received.